Brown is on a coaching assignment in Barbados and will not be back in time for the three-day match against Bedfordshire, which starts tomorrow at Luton. It is the first time the off-spinner has missed a Championship match since July 2008 – also against Bedfordshire – when an ankle injury ruled him out.

Left-arm spinner Watson, who played in the recent victory over Hertfordshire and was named man-of-the-match after a six-wicket haul in last Sunday’s Carter Cup final, is likely to have a significant bowling role over the next three days at Wardown Park.

Walker said: “It is a blow to lose Brownie because he is a key player with his wickets and his ideas and he bowls a lot of overs for us.

“But it gives an opportunity to Ashley, who has been in good form with the ball. He will need to bowl a lot more in this game and that’s not something that worries me at all.”

Fellow left-arm spinner Walker watched Watson take six for 16 to seal Norwich’s Carter Cup win and he added: “I think the pitch was right up Ashley’s street, but you’ve still got to bowl in the right areas and he fully deserved his man-of-the-match award.”

Walker himself had been an injury doubt for the trip after suffering a back injury during the innings and 33-run victory over Hertfordshire, but is fit to play for Swardeston against Horsford today and will lead Norfolk tomorrow.

He said: “I’ve had a couple of trips to the chiropractor, there were a few clicks and it’s done the job. There’s still a bit of pain, but nothing to worry about.”

The Norfolk side shows three changes, with seamer Kieran Bunting coming in for Brown, Peter Lambert replacing the unavailable Luke Caswell and Sam Arthurton returning in place of Carl Rogers, who has retired from county duty.

Rogers’ absence creates a vacancy at the top of the order and Walker admits there are a few candidates to be the long term successor to the veteran opener: “Stephen Gray could potentially open in this match, but we’ll have a look at the pitch – he might not open if we field first and he’s had 90 overs behind the stumps because that can be quite hard for a keeper.

“In the longer term there’s a few people knocking on the door and it might be that one of the middle order batsmen moves up. Luke Caswell could open the batting and Harry Bush is another option.”

Last year’s Championship clash with Bedfordshire at Manor Park saw Norfolk win by one run in a thrilling finish, handing Walker his first victory as county skipper.

Bedfordshire have yet to win in the Championship this season and have lost their last two matches, against Cumberland and Buckinghamshire.

Norfolk need to take maximum points against Bedfordshire and hope that leaders Buckinghamshire collect less than five points from their game at Northumberland.

Cambridgeshire (61 points), who travel to Staffordshire, and Cumberland (60), who host Hertfordshire, are the other sides in contention.

Walker admits finishing top is a long shot for Norfolk: “It’s possible but probably unrealistic,” he said. “We’ve just got to worry about our own game and try to take maximum points. We’ve played some decent cricket this year, but if you worry too much about other games you can get yourselves in trouble.”